Heretofore, quantum wire and well arrays have been developed for low-current threshold semiconductor laser applications primarily because of their strong optical anisotropy. See M. Tsuchiya et al, Physical Review Letters, 62, 466, 1989. The fabrication and characterization of such quantum wire and well structures are found in publications such as, M. A. Reed et al, Physical Review Letters, 60, 535, 1988 (in connection with quantum coupled electron device architectures), M. Watt et al, Semiconductor Science and Technology, 5, 285, 1990, Y. Iimura et al, Japanese Journal of Applied Physics, 28, 1083, 1989, and E. Colas et al, Applied Physics Letters, 55, 867, 1989.
In conventional single quantum well laser devices, the light confinement length, l, where l.about..lambda./2 (wherein .lambda. is the wavelength of the light), is much greater than the width a of the active region of the laser device. This is illustrated in FIG. 2. Line 1 represents the confined electromagnetic wave and .lambda. represents the entire wavelength. As shown, the width a of the active region of the single quantum well 3 is significantly smaller than that of the wavelength .lambda.. Also as shown, the electrons, the wavefunction and energy level of which are represented by line 2, are confined within the single quantum well. The typical ratio of a/l is only on the order of a few percent and accordingly, because it is proportional to (a/l).sup.2, the gain of single quantum well laser devices is also relatively small. In single quantum wire laser devices, the geometric overlap is even smaller because the gain is proportional to (a/l).sup.4. The limitation this causes is that the confinement length l of the TE and TM modes is physically constrained and cannot be decreased in single connected waveguides in order to increase the gain because the cut-off frequencies of the structures are greater than the lasing frequencies. Typically, the cut-off frequencies are generally described as .omega..sub.n .varies. c/nl.fwdarw..infin. as l.fwdarw.0. This is graphically shown in FIG. 3. Accordingly, the gain enhancement of quantum well and quantum wire laser devices has been heretofor limited because of this physical constraint. Therefore, there is a need to enhance the gain of laser devices based on quantum well or wire technology. The present invention addresses this need.